THE EFFECT OF POTENTIAL ON METASTABLE PITTING OF AMORPHOUS NI-ALLOY

The effect of potential on metastable pitting of amorphous NiCrFeSiB a lloy in neutral NaCl solution was studied by electrochemical method. A t constant potentials, the growth current of metastable pits increased in the form of I-I-0=k(t-t(0))(2), with the parameter k values follow ing log-normal distribution. As the potential was increased, both the average k and minimum k values increased. The peak currents of metasta ble pits also followed a log-normal distribution with a rise with pote ntial. A two stage growth process of metastable pitting was suggested. (C) 1997 Elsevier Science Ltd.